/*******************************************************************************
 * Copyright 2011, 2012 Chris Banes.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.zhoukl.androidRDP.RdpViews.photoview.gestures;

import android.content.Context;
import android.util.FloatMath;
import android.util.Log;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.ViewConfiguration;

public class CupcakeGestureDetector implements GestureDetector {

	protected OnGestureListener mListener;
	private static final String LOG_TAG = "CupcakeGestureDetector";
	float mLastTouchX;
	float mLastTouchY;
	final float mTouchSlop;
	final float mMinimumVelocity;

	@Override
	public void setOnGestureListener(OnGestureListener listener) {
		this.mListener = listener;
	}

	public CupcakeGestureDetector(Context context) {
		final ViewConfiguration configuration = ViewConfiguration.get(context);
		mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
		mTouchSlop = configuration.getScaledTouchSlop();
	}

	private VelocityTracker mVelocityTracker;
	private boolean mIsDragging;

	float getActiveX(MotionEvent ev) {
		return ev.getX();
	}

	float getActiveY(MotionEvent ev) {
		return ev.getY();
	}

	public boolean isScaling() {
		return false;
	}

	@Override
	public boolean onTouchEvent(MotionEvent ev) {
		switch (ev.getAction()) {
			case MotionEvent.ACTION_DOWN: {
				mVelocityTracker = VelocityTracker.obtain();
				if (null != mVelocityTracker) {
					mVelocityTracker.addMovement(ev);
				}
				else {
					Log.i(LOG_TAG, "Velocity tracker is null");
				}

				mLastTouchX = getActiveX(ev);
				mLastTouchY = getActiveY(ev);
				mIsDragging = false;
				break;
			}

			case MotionEvent.ACTION_MOVE: {
				final float x = getActiveX(ev);
				final float y = getActiveY(ev);
				final float dx = x - mLastTouchX, dy = y - mLastTouchY;

				if (!mIsDragging) {
					// Use Pythagoras to see if drag length is larger than
					// touch slop
					mIsDragging = FloatMath.sqrt((dx * dx) + (dy * dy)) >= mTouchSlop;
				}

				if (mIsDragging) {
					mListener.onDrag(dx, dy);
					mLastTouchX = x;
					mLastTouchY = y;

					if (null != mVelocityTracker) {
						mVelocityTracker.addMovement(ev);
					}
				}
				break;
			}

			case MotionEvent.ACTION_CANCEL: {
				// Recycle Velocity Tracker
				if (null != mVelocityTracker) {
					mVelocityTracker.recycle();
					mVelocityTracker = null;
				}
				break;
			}

			case MotionEvent.ACTION_UP: {
				if (mIsDragging) {
					if (null != mVelocityTracker) {
						mLastTouchX = getActiveX(ev);
						mLastTouchY = getActiveY(ev);

						// Compute velocity within the last 1000ms
						mVelocityTracker.addMovement(ev);
						mVelocityTracker.computeCurrentVelocity(1000);

						final float vX = mVelocityTracker.getXVelocity(), vY = mVelocityTracker.getYVelocity();

						// If the velocity is greater than minVelocity, call
						// listener
						if (Math.max(Math.abs(vX), Math.abs(vY)) >= mMinimumVelocity) {
							mListener.onFling(mLastTouchX, mLastTouchY, -vX, -vY);
						}
					}
				}

				// Recycle Velocity Tracker
				if (null != mVelocityTracker) {
					mVelocityTracker.recycle();
					mVelocityTracker = null;
				}
				break;
			}
		}

		return true;
	}
}
